{
  "bibcode": "2005GCN..3391....1C",
  "body": "S. Bradley Cenko, B. T. Soifer, Chao Bian, Vandana Desai, S. R. Kulkarni\n(Caltech), Edo Berger (Carnegie), Arjun Dey and Buell T. Jannuzi (NOAO)\nreport on behalf of a larger collaboration:\n\nWe have imaged the error circle of the Swift GRB 050509b (GCN 3381) with\nthe Keck Low Resolution Imaging Spectrometer (LRIS) mounted on the Keck I\ntelescope.  We have obtained two epochs of simultaneous imaging in the g'\nand R filters.  The first epoch consisted of 4 x 300 s images taken at a\nmean time of approximately 7:00 UT 9 May (~ 3 hours after the burst).  The\nsecond epoch consisted of 3 x 300 s images taken approximately 1.5 hours\nlater.\n\nInside the XRT error circle, we find four sources, three of which are\nmarginal detections.  The brightest source is located at (J2000.0):\n\n\tRA: 12:36:13.7\n\tDec: 28:58:57.3\n\nThe source appears to brighten slightly from our first to our second\nepoch.  Under close inspection, it also appears to be embedded in an\nextended nebular galaxy.  An image can be found at:\n\nhttp://www.srl.caltech.edu/~cenko/grb050509b/050509.jpg\n\nFurther observations are planned.",
  "circularId": 3391,
  "createdOn": 1115631409000,
  "email": "cenko@srl.caltech.edu",
  "subject": "GRB 050509b: Possible Optical Counterpart",
  "submitter": "S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>",
  "eventId": "GRB 050509B"
}